


The Hound of Hogwarts

by HarrisonHolmes2014



Series: Sherlock Holmes and the Wizarding World [2]
Category: Harry Potter - J. K. Rowling, Sherlock (TV), Sherlock Holmes & Related Fandoms
Genre: Canon Divergence - The Hounds of Baskerville, Crossovers & Fandom Fusions, Dark Magic, F/M, Forbidden Forest, Hogwarts AU, Hogwarts Second Year, Kidlock, Magic, Magical Experiments, POV Third Person Omniscient, Potterlock, Slytherin Pride, sort of canon compliant
Language: English
Status: Completed
Published: 2016-05-20
Updated: 2016-06-21
Packaged: 2018-06-09 06:48:23
Rating: Teen And Up Audiences
Warnings: No Archive Warnings Apply
Chapters: 11
Words: 11,324
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/6894394
Author URL: https://archiveofourown.org/users/HarrisonHolmes2014/pseuds/HarrisonHolmes2014
Summary: <blockquote class="userstuff">
              <p>Sherlock Holmes' second year at Hogwarts starts out normally enough (for a school of magic), and he fears it will turn out to be a rather dull year. But then Gryffindor Henry Knight comes to Sherlock with an odd story: Henry keeps finding mysterious, unnaturally large pawprints wherever he goes. This fact, and other students' whispers of "weirder-than-normal" animals in the Forbidden Forest, convince Sherlock, John and Molly to trace the beast.</p>
            </blockquote>





	1. The Return to Hogwarts

**Author's Note:**

> "The Hounds of Baskerville" is my favorite Sherlock episode, and the novel is my favorite ACD story. I CAN'T WAIT to work on this story!

After a long and tedious summer, the first of September arrived once more. Sherlock was chomping at the bit to start his second year at Hogwarts School of Witchcraft and Wizardry. The summer, though enjoyable as he and his family had spent a month at their country house, had a distinct lack of mysteries and intrigue. Plus, Sherlock had missed his classes, the castle and, above all, the two friends he'd made during his first year: John Watson and Molly Hooper (though he'd never admit to missing Molly, not out loud anyway). All in all, the time was ripe for him to load his trunk and lock Cygnus, the barn owl Mycroft had given him as a twelfth birthday gift, safely into his cage.

The Holmes family's trip to King's Cross went without a hitch. As usual, they met the Hooper family on the platform so that the fathers could load the trunks onto the Hogwarts Express. Molly, too, was carrying a new pet: a gray tabby cat. Though she still blushed and stammered when speaking to Sherlock, she didn't seem as bad as usual. Perhaps she was getting more comfortable around him, after helping him solve last year's Veritaserum mystery. To both their delight, they were to share the train ride with another friend.

"Sherlock! Molly!" The shout came from a short, stocky figure emerging from the steam. John Watson, their fellow investigator and second-year, ran forward to greet them both. Just after him ran a similarly built girl with curly, sandy brown hair like his: John's fifth-year sister, Harriet. 

"Care to share a compartment on the ride?" John asked Molly and Sherlock.

"Sure," they answered in sync. As the station guards began closing doors, the trio said their goodbyes to their families. They climbed aboard, accompanied by Harriet. Turning to the other girl, Molly asked, "Would you like to join us, Harriet?"

"No, thanks, I said I'd meet Clara. And you can call me Harry, by the way, everyone does." She gave John a one-armed hug and dashed off down the train corridor.

"Clara?" Molly asked, turning to John.

"Friend of hers."

"More than that, I think," Sherlock said. Molly and John both rolled their eyes, but the gesture was exaggerated. He knew they secretly enjoyed his deductions. "Would a sterling-silver necklace with the letters C and H on the same chain be something only a friend would give?"

"All right, all right, you got her," said John gruffly as he pushed open an empty compartment door. But Sherlock caught a grin tugging at the other boy's lips.

"You should put that in your serial, Watson." A most unpleasant voice came at the compartment door. The three turned to see an old enemy of Sherlock's standing there: Sally Donovan. At her side stood Phil Anderson, a gangly Ravenclaw in their year who obviously fancied her, from the way he followed her around like a puppy.

"Serial?" Sherlock asked, turning to glare at John. "What's she on about?"

John blushed and shifted his feet a bit. "I wrote down what happened last year. With the Veritaserum," he explained. _"Someone _working on the school newsletter nicked it from my dormitory - " he glared at Sally - "and, well, now Professor Binns want me to keep writing about anything that comes up. He's head of the newsletter, you know."__

 _ _"Did you_ really_ learn the Earth goes round the sun in Astronomy last year?" sniggered Anderson. Sherlock felt the heat rising in his cheeks. From his pocket, his thestral tail-hair wand emitted a reddish glow as he blushed. How inconvenient.

"See, Phil? He's exactly what I said he was. That's something only a freak wouldn't know," Sally observed, her dark eyes gleaming with malice.

"Get out."

The two words shocked everyone in the compartment. Molly, normally so calm and docile, was on her feet, her wand drawn and pointing directly into Sally's face. Sherlock, even through his embarrassment, registered with surprise that Molly's cheeks were glowing red too, but with anger. Sally, not dumb enough to pick a fight with the teachers' compartment nearby, sneered at her and walked away, Anderson following behind. Molly threw herself back into her seat and shoved her wand away, and after sharing a surprised glance John and Sherlock joined her. From the unoccupied seat beside John came a soft rustling and hooting as his owl Hermes, also a barn owl, investigated Cygnus from his cage. Molly's cat, completely indifferent, curled up in her lap, purring quietly as it closed its eyes.

"So, the serial," Sherlock said, to cover the stickiness of Molly standing up for him.

"Yeah," John said vaguely. "I didn't use our names, because you and Molly didn't know anything about it and I didn't want to mention you by name without your saying it was okay. It was just supposed to be for me anyways. But Donovan's probably spread the word around that it was us."

"So we're famous," grunted Molly.

"Maybe, yeah, but I can't stop writing now," sighed John. "I already promised Professor Binns I'd do another set for this year's newsletter, and the writers are getting paid. Three Galleons for each installment."

"Good for you," Sherlock said grudgingly. There was a moment of silence, and then curiosity got the better of him. "What did you call it? Your serial?"

" 'A Study in Veritaserum,' " John replied, going an even deeper shade of scarlet.

"A Study in Veritaserum," Sherlock repeated. "Nice title." He held in a sigh. He'd hoped his second year at Hogwarts would be interesting. But he had to admit, this kind of interesting wasn't exactly what he had in mind.


	2. Henry Knight

To Sherlock's dismay, the first month of term was perfectly normal. It was wonderful to be back at school, brewing up new potions and having the whole Hogwarts library at his fingertips once again. But two new developments occurred that he didn't particularly care for. John, after a successful tryout, was now a Beater on the Gryffindor Quidditch team and had to report to practice three nights a week. Then, in the third week of term, Molly told him that Professor Sprout, Herbology teacher, had approached her for assistance in caring for a new crop of Mandrakes, an activity that kept Molly occupied two nights a week. While Sherlock was happy for his friends - it took great skill to have these new positions, he knew - he was more bored than ever in the hours when they weren't around.

Making matters even worse was the sudden fame Molly had predicted on the train. Word had indeed gotten around the school, and it seemed that everyone knew the identity of John Watson's three main serial characters. The school idiots were, all of a sudden, much more visible than ever. People took to stopping Sherlock in corridors and asking him to tell them all manner of things. In one day, he received requests to give answers to a Charms quiz, find a runaround boyfriend, and track down Bluebell, a first-year's missing cat that had suddenly started glowing in the dark. He refused all requests, of course, but it irked him that his refusals didn't make people stop asking.

So, by the first week of October, Sherlock was practically twitching at news of possible, _actual _cases. At long last, one day just after Transfiguration, his prayers were answered. As he and John were filing out of the classroom, someone cried out, "Hey, Holmes!" Suppressing a groan, Sherlock turned.__

__A third-year Gryffindor boy with closely cropped brown hair was pushing his way through the corridor towards them. The boy stopped in front of them, shifting his feet in an embarrassed fashion, his gray eyes on the stone floor. "Hi, Henry," said John, and Sherlock realized it was one of the Gryffindor Quidditch team's Chasers.__

"I was wondering if you could help me," Henry stammered. 

__"No, I don't know the answers to your Transfiguration homework, and I can't find your missing pet owl," Sherlock snarled, slinging his bag over his shoulder. "Now, if you'll excuse me - "_ _

__"I'm serious," said the other boy quietly. And Sherlock saw it in his face: he was a little pale, and there were worry lines around his eyes. Not to mention the dark shadows under them. Sherlock relaxed a little._ _

__"What seems to be your trouble?"_ _

__The boy looked around. Lowering his voice, he said, "I can't talk about it now. Could you meet me in the Gryffindor common room tonight after dinner? Ask for Henry Knight if you can't find me."_ _

__Sherlock and John traded glances. "All right," Sherlock agreed. "My friend John here will let me in."_ _

That night after dinner, John took Sherlock up to Gryffindor Tower to meet Henry Knight. Though he would always prefer his own common room, Sherlock was favorably impressed with Gryffindor's. It was full of squishy crimson armchairs and deep red tapestries that captured the fire's warmth, and commanded a lovely view of the Forbidden Forest. Standing by the stone fireplace, shifting his feet again, was Henry. "Oh, good, you're here," he said, leading Sherlock and John to an empty table at the edge of the room. The three boys sat, and Sherlock waited for Henry to speak first.

"I've had a bit of a problem, Holmes," Henry began, picking at one of his nails. "Maybe you and your friends can help me."

"Only if you tell your story," Sherlock encouraged him tartly. John gave him a sidelong glance, but Sherlock kept his eyes on Henry.

"I guess it all started last year, with my brother David." Henry gave a little sigh. "He's three years older than me, but we were still close. We used to go for walks along the edge of the Forbidden Forest. Sometimes we went in the Forest too; David loved animals and Care of Magical Creatures, so he had special permission to go inside and study the animals there, as long as he didn't go off the main path. He even used to help Hagrid with animal-related jobs deep in the Forest. David had all sorts of stories about the stuff that lived in there, chasing unicorns and talking to centaurs..."

"Yes, yes, skipping ahead to what actually happened," said Sherlock irritably, rolling his hand in the air to make the point.

"One night last spring, we were supposed to go for our walk, but David didn't show up in the common room," Henry continued, his voice more urgent than before. "So I went down to the forest edge. He came staggering out of the trees, all..." Henry swallowed. "He was all white and shaky, talking to himself. He didn't know who I was, didn't even remember his own name. All he kept saying was the word 'hound.' " Another pause, in which Henry gazed out at the dark, swaying trees below. "David's in St. Mungo's Hospital now. Badly performed Memory Charm, combined with stress from O.W.L. exams, they told me. Apparently the charm can make you go mad if it's not done exactly right and you're already under pressure."

There was a long silence. John finally broke it by saying, "Well, I'm sorry about what happened to your brother. But what does that have to do with us?"

Henry shifted in his seat again. A dull red flush was creeping into his cheeks, but his jaw was set in determination. "You may laugh at me," he said sullenly. "But I know what I've been seeing. I still go for walks down by the Forest. The first night back here I went, and I saw..."

He broke off again, paleness mixing with the red. "Footprints," he choked.

"A boy's or a girl's?" Sherlock asked, bored.

"Neither," stammered Henry. "And they've kept showing up, everywhere I go on the grounds, always before I get there. On the way to Herbology, at the Quidditch pitch, on the path to Hogsmeade..."

"Obvious," Sherlock said quickly, nearly rolling his eyes in exasperation. "Someone knows about your brother, decides to have a little fun with you, learns your schedule, plants footprints wherever you go to scare you. Boring!" He stood up, wanting nothing more than to go back to the Slytherin common room. But Henry's next few words, spoken in a frightened, strained voice, stopped Sherlock in his tracks.

"Holmes, they were the footprints of a gigantic hound!"


	3. Mundungus Fletcher's Testimony

Sherlock, deeply intrigued by Henry Knight's story, agreed to take the case. The next day, during one of their joint free periods, Sherlock met with Molly and John to update her and discuss how to proceed. As he'd expected, Molly was interested and excited to work with him again.

" "A gigantic hound'?" she repeated when Sherlock described Henry's words. They stood in the main school courtyard, in a secluded corner that protected them from both the wind and possible eavesdroppers. "What d'you two think? Werewolf? There's supposed to be some living in the Forbidden Forest, I've heard."

"No, a werewolf would've killed David Knight, or turned him into one," John said.

Sherlock nodded, pulling his cloak tighter around him in the chill October wind. "Sounds to me like it's something more odd than a werewolf. I had a thought..."

"What?" asked Molly.

"Well, someone might be performing experiments on animals," he explained. "Magical experiments, seeing what would happen. But first, we should make absolutely sure that Henry isn't the only one seeing clues to this 'hound.' Ask around in Gryffindor and Hufflepuff to see if anyone else has seen any weird animals around here, or clues to them. Footprints, dung, food remains, anything like that. Molly, you're still friends with that Ravenclaw girl, right? Soo Lin?"

"Yes."

"Good, ask her to nose around in Ravenclaw for us. Meet again when we all have something?" Molly and John nodded, and the three went their separate ways as the bell rang.

The trio spent the next few days searching for other student accounts. As Sherlock was not popular amongst the Slytherins, due to his friendships with John and Molly, he had a hard time wheedling information out of the few who deigned to speak to him. John reported no other Gryffindor encounters, though Henry was still finding prints. Molly's labors, on the other hand, were more fruitful.

"Two people in Hufflepuff have seen traces of something 'weirder than normal' near the Forest," she reported to the boys, reading from a small book in which she'd kept notes. "A Louise Mortimer, third-year, a very good friend of Henry's. She said she'd seen a set of pawprints leading away from the vegetable gardens. The other, Gary Bennice, is a shopkeeper's son from Hogsmeade. He says he found huge prints leading from his street towards the castle. And Soo Lin knows a Ravenclaw student who tried to trace a set of prints, but she got caught trying to get into the Forest."

"Good," said Sherlock. "Shame it's all only prints, though, those could be faked."

"I don't think so," John said quietly. When Molly and Sherlock both looked at him curiously, he explained, "One of the Gryffindor boys told me he knew someone who'd actually seen this hound. Someone named Fletcher from Slytherin, d'you know him?"

"No," said Sherlock, "but I know him by sight. I'll see if I can get him to talk."

That night in the Slytherin common room, Sherlock waited by the stone wall entrance. Hearing footsteps, he rose to his feet. Molly slowly emerged from the gloom, looking nervous. "What am I supposed to say again?" she said as Sherlock gave the password ("draco").

"Just introduce the story. Then let me do the talking." Sherlock spotted the boy they were looking for. Mundungus Fletcher, a seventh-year, was at his habitual seat in the farthest corner from the fireplace. Even from across the room Sherlock could smell a hint of stale tobacco. He and Molly joined Fletcher at the table, and the older student gave them a suspicious look from beneath matted ginger hair.

"Well, 'ello there, 'olmes. And who's this pretty little lady from...'ufflepuff?" The last word was spoken with some disdain, as his drooping eyes lingered on the black-and-yellow crest on Molly's robes.

"Friend of mine, Molly Hooper."

"Well, any friend of a Slytherin mus' be trus'worthy," sighed Fletcher. "Wha' brings you to my table? Need a little somethin' to keep the ol' brain sharp for exams?"

"No, thanks," Molly said. Calmly, she went into the story she and Sherlock had agreed on. "You know Henry Knight in Gryffindor? He reckons there's some sort of mad dog out in the Forbidden Forest."

"Yeah, I've 'eard," said Fletcher gruffly.

"I bet my friend Molly here five Galleons you couldn't prove you'd seen it," said Sherlock.

Fletcher smiled. The gambling light was in his eyes, as Sherlock had seen it glow at Quidditch matches. "Well, you're gonna lose your Galleons, mate," he said. "I seen it. It was foggy, mind, the night I saw it, but me eyes didn't lie. Big, black thing all glowin' round the edges, it was. Red eyes like a devil straight outta hell. Here, I got a picture, used a special photo-developin' potion for it."

He held up a Wizarding photograph. Squinting at it, Sherlock saw a large, black blur darting between a few fog-shrouded trees. _"That's _your proof?" he said, making sure to accentuate a sneer. "Not much to go on, is it? Anyone can fake a photograph. I win the bet, Molly!"__

Fletcher's face reddened slightly. "You listen 'ere, boy," he said darkly. "Sometimes, smart kids get bored. 'Specially the Ravenclaws an', sadly, the Slytherins. They wanna know more'n they should learn in school. I seen a few of 'em in my day, inventin' nasty potions an' all sorts of mad spells." He paused, clearly for drama. "I 'ad a friend last year who wanted to know more'n 'e should've too. One night 'e met some other students in the Forbidden Forest, some folks experimentin' on some animals from Care of Magical Creatures. Came back white as parchment. Told me, 'I've seen things tonight, Dung, that I never wanna see again.' "

"Like what?" said Molly.

"Rats the size o' dogs," said Fletcher, reaching into his bag. "An' dogs the size o' horses." He held up a plaster cast, of the type used to make models for Care of Magical Creatures classes. Sherlock looked at it and couldn't help a shiver going up his spine.

Inside the cast was a pawprint the size of a cart-horse's hoof.

Though she was obviously horrified too, Molly managed a small smile. "We did say five Galleons?"


	4. Beryl Stapleton

Sherlock passed on the results of his conversation with Mundungus Fletcher the next day in Potions class. Though Sherlock generally paid attention in this, his favorite class, the message to John couldn't wait. So, he made sure the two of them shared a table, alone. As they were setting up their cauldrons, Sherlock told John what Fletcher had said, and what he and Molly had agreed they should do.

"I think we should try and do two things," Sherlock said quietly as Professor Snape magicked the ingredients for this lesson's potion (Hiccuping Potion) onto the blackboard. "We need to find out who's doing magical experiments on animals these days. Fletcher didn't say when his friend saw the experiments, but it might've been a while ago. Then, we need to try and find out where this 'hound' lives, who's taking care of it, and so on."

John nodded, chopping up his daisy roots. "Fletcher did say his friend saw this in the Forest, right?"

"Unfortunately, yes."

John said nothing, but Sherlock had to hide a grin. He knew better than anyone John's secret love of danger.

Counting Molly's friend Soo Lin, Sherlock now had a pair of eyes in every Hogwarts House. He instructed the other three to watch the members of their Houses carefully, to monitor who was leaving the common rooms at night. After a few quiet and sleep-deprived nights, Molly came up to Sherlock in the Great Hall at breakfast. "It's a Ravenclaw," she said quietly, so that none of the other Slytherins could hear. "Wait in the Entrance Hall. I'll get John."

A few minutes later, as Sherlock waited, Molly brought John and another person out. She was a small, slim girl with very straight black hair. "Sherlock, John, this is Soo Lin Yao," Molly said, gesturing to the girl.

"Nice to meet you," she said. Her dark eyes crinkled in a smile as she shook hands with John and then Sherlock.

"So, what do you have for us?" Sherlock said quickly.

"The girl's name is Beryl Stapleton," said Soo Lin. "Two out of the last three nights I saw her sneaking out of the common room."

"Stapleton," Sherlock repeated. He knew that name. In a flash it came to him: Bluebell. A first-year Ravenclaw, Kirsty Stapleton, had told him her vanished cat had started glowing in the dark. He shared this information with the others.

"You think Beryl stole her sister's cat?" Molly gasped. She looked horrified at the very thought.

"Yes," said Sherlock grimly. "I think we should investigate Miss Stapleton a bit deeper. Soo Lin, can you keep watching her? Send Molly a message as soon as you see Stapleton going out again."

Soo Lin agreed, and for another couple of days there was no word from her. But then Molly came up to Sherlock just after Herbology, a small note clutched in her dirt-smeared hand. "Soo Lin's owl was waiting for me outside the Hufflepuff common room," she said. Sherlock unfolded the note and the two of them bent over it: _She's going to the Forest tonight. Heard her telling her friend she was "going for a walk." SL ___

That night, Sherlock, Molly, and John found themselves once again out of bed after hours. Molly, from her friendship with Soo Lin, knew the way to Ravenclaw Tower, so she led the group through the moonlit halls. The three of them crouched behind a suit of armor resting near the common room entrance. With a creak, its helmeted head turned to look at them, but it offered no comment. They waited; the thestral wand, to Sherlock's annoyance, refused to stop giving the quivering, silvery light it emitted when he was anticipating something. He stuffed it under his cloak in the hope that would muffle it.

Then, a soft footstep came from the Ravenclaw common room entrance. Peeking out from behind the armor, Sherlock saw a rather nondescript girl with her brown hair pulled back in a bun. A blue and bronze Prefect pin gleamed on her chest. Anxiously Beryl Stapleton glanced up and down the dark corridors, then set off at a purposeful, yet silent, walk. Motioning for the other two to follow, Sherlock crept after her. His wand, finally grasping how secretive they had to be, finally stopped glowing.

The three of them trailed behind Stapleton all through the castle. Once or twice she cast a look over her shoulder, but as the second-years stayed hidden in the castle's many shadows, she didn't seem to notice she was being followed. Out the front doors, across the sweeping lawns and to the edge of the Forbidden Forest, Stapleton kept her purposeful walk. She led Sherlock, John, and Molly into a small clearing just off the Forest path. Crouching behind a massive sycamore, they watched as she raised her wand and murmured, _"Accio Cat." _Branches rustled in front of her, and the three younger students watched in amazement as a small white cat came zooming out of the trees, to halt at Stapleton's feet. The cat emitted a faint bluish light.__

Sherlock was the first to emerge. "Evening."

Stapleton jumped nearly a foot in the air. She dropped the glowing cat, which made a bid for freedom, but Molly pulled it back with the same charm she'd used. _"Expelliarmus!" _John said, and Stapleton's wand flew from her hand and landed in John's. It was dark, but by the cat's glow Sherlock could see a very ugly look on her face.__

"Who are you?" Stapleton demanded. "Why did you follow me here?"

"Maybe a better question is why you're doing illegal experiments," Molly snapped, stroking the glowing cat.

"Are you going to tell your sister what happened to Bluebell, or should I do it?" Sherlock said sweetly, his wand still aimed at Stapleton.

She seemed to sag before them as all the fight went out of her. "What do you want from me?" she asked.

"First of all, why?" Sherlock said.

Stapleton shrugged. "Why not?" she said. As Molly opened her mouth to protest, enraged, Stapleton continued, "I haven't done anything to _hurt _Bluebell. It's a charm I invented, the Glowing Charm. The incantation is_ Meridio,_ in case you're interested. I'm just keeping Bluebell here because I haven't worked out a countercharm yet. Once I do, Kirsty will get her cat back and my curiosity will be satisfied."

"Why your sister's cat?" said John.

"She was getting on my nerves."

Sherlock did not wince at this, as John and Molly did. It sounded like something he himself might do to Mycroft. "So who else is doing experiments on animals around here?" he demanded.

Stapleton thought. "No one I'm aware of," she said, after a long pause. "They wouldn't exactly go shouting about it."

"No, I suppose not." She wasn't looking Sherlock in the eyes. That alone told him that she knew more than she was letting on, but there was no way to get it out of her right now. Disappointed, he lowered his wand. "I believe we can trust you to keep quiet about us three being out of bounds. Professor Flitwick would be very interested to hear about Bluebell, I expect." With that, Sherlock led the way out of the clearing.

"So, what exactly have we found out?" said Molly once Stapleton was out of earshot.

"That Beryl Stapleton performs illegal experiments when a book can't answer her questions," said Sherlock. "What we should be asking ourselves is: has she done anything to animals more dangerous than cats?"

John had the last word of the evening as he eased the front door open. "To be fair, that is a pretty big field."


	5. Night of the Hound

Sherlock couldn't get a hold of Henry Knight until two days after the encounter with Beryl Stapleton. But he caught Henry after Transfiguration, walking through the corridors with John. Both boys' heads turned on Sherlock's approach. "Oh, hi, Holmes," said Henry. "John here was telling me about what you've found out. So it isn't just me?" he said hopefully.

"No," Sherlock said. "A few other people have seen signs of it. It doesn't seem to be preying on anyone in particular."

"This is good," Henry gulped, even though he looked shaken. "This is really good. I'm not crazy." There was a slight pause, where the clattering rain outside added an ominous note to their conversation. "So what's the plan now?"

"We take you back to the Forbidden Forest, where you used to walk with your brother David," said Sherlock

"Okay."

"Then we wait and see if anything attacks you," he finished matter-of-factly.

"Sorry, what?" yelped Henry. "You want me to be in that...that _thing's _path?"__

"That's your plan?" John said sharply, almost at the same time. "Sherlock, that's not a plan at all." 

__Sherlock glared at both of them. "Well, there's only one way to start trying to catch this hound, isn't there?" he said. "Find out where it lives." Neither John nor Henry looked particularly thrilled, but they both agreed to go to the Forest that evening. Dusk was when Henry usually went for his walks, so Sherlock figured that would be a good time to try and lure the beast out. He and John told Molly about their plans, and she agreed to come. That way, nobody would be left alone if the group had to split up._ _

Everything went according to plan. Henry, Molly, John, and Sherlock arrived at the edge of the Forest around seven, just after dinner. The groundskeeper, Hagrid, was working in his garden and gave the four students a wave as they passed. Second-years were allowed on the grounds until darkness fell, so they were well within their time limit. It was a lovely October evening: the crisp, spicy smell of fallen leaves tingled in their nostrils and the setting sun turned the treetops golden and scarlet. They loitered until Hagrid went back into his cabin and drew the curtains. Then, Sherlock turned to Henry, saying, "Lead the way."

Nervously, Henry stepped forward and onto the main forest path. Though it was still light out on the grounds, here the trees cast long black shadows and the light dimmed into a greenish gloom. All of them whispered _"Lumos," _and four wand tips ignited. At each snap of a branch, each rustle of leaves, they pointed their wands into the darkness, but found nothing. When the path forked about twenty yards in, they split, John and Molly taking the left, Sherlock and Henry taking the right.__

"Tell me more about your brother," Sherlock said, in a lower voice than normal. There was no one around, but he still had the prickly feeling of unseen eyes and ears in the trees. "Friends, other hobbies besides animals...?"

"Well, David had a really good friend in Ravenclaw," said Henry. "Bob Frankland, he's a sixth-year now. He likes Care of Magical Creatures too. He and David used to spend hours talking about lessons, and Bob even came with us on walks once or twice." Henry paused, investigating a space between a rowan and a fir tree. "Bob's been really nice to me since David went into hospital," he said. "Kind of keeps an eye on me, gives me help if I need it." Sherlock nodded, making a mental note to meet this Frankland as soon as possible.

He was about to reply to Henry when they heard it. A long, low animal moan whispered through the trees; it was impossible to tell from what direction. As the two boys frantically pointed their wands into the shadows, the beams dancing, the moaning grew louder. It rose in both volume and pitch, transforming quickly into a howl and then a piercing, keening scream. A branch snapped behind Sherlock and he whirled around, wand at the ready.

A monstrous black shape, the size of a small horse, with four long, powerful legs...Shining white teeth as long as his own hand...Glowing red eyes...Sherlock opened his mouth to cast a spell, or scream (he didn't know which), but the thing was gone before he was even sure he'd seen it. The howling faded and the Forest returned to silence.

"Oh, my God," Henry muttered. He turned a starkly white face to Sherlock. "Did you see that?" he squeaked.

More rustling nearly made the two jump out of their skins, but it was only John and Molly. Both of them, though unhurt, looked deeply unnerved. "We heard something," Molly said quickly. "A sort of howling - what in the name of Merlin happened to you two?" she added, seeing Sherlock and Henry's pale faces and wide eyes.

"We saw it," Sherlock said shortly. Desperate to get away from the Forest, he led the way back down the path. It took all his strength to not run. "We saw the hound."

"What?" said John. "Are - are you sure?"

"Sherlock, Henry, it was dark and scary and easy to make a mistake," Molly said uncertainly.

Sherlock shook his head. "When you've ruled out the impossible, whatever's left must be true. No matter how unlikely it is," he said. Mercifully they reached the edge of the Forest and the open grounds. Henry didn't say goodnight when they reached the Entrance Hall; he looked as if he might never speak again. He and John went up the marble staircase to Gryffindor Tower, leaving Sherlock and Molly alone. A quivering, puke-green light bounced off of the stone walls. Sherlock looked down: it was the thestral wand, trembling along with his hand.

"Huh," he said quietly. He held up his wand, showing Molly how badly he was shaking. "Look at that. I'm afraid. I always thought I could hide it, but...my body and my wand won't lie for me."

Other people, Sherlock later reflected, would've said something, tried to use empty words to soothe. But Molly didn't. She put one hand on his wand arm and led him through the Slytherin tapestry without speaking. She saw him all the way down the dungeon corridors and waited until he'd gotten into the common room before leaving him. It was only when the stone door closed behind him that Sherlock realized: the puke-green wandlight, while still there, had dimmed a bit at her touch.


	6. Acronyms

It took a couple of days for the shock of seeing the hound to wear off. Making matters worse was that Sherlock couldn't get the picture of the beast out of his mind. Most of him didn't want the hound gone from his mind. How else would he figure out who was responsible for it, if he refused to think about it? However, it would've been nice not to have the black-furred, red-eyed monster stalking his dreams along with his waking thoughts.

But one of those night encounters turned out to be helpful. Three nights after the sighting, a few days before Halloween, Sherlock awoke gasping for air and sweating from another hound nightmare. Shaking, he pushed aside the emerald velvet hangings around his bed. He poured himself a goblet of water from the silver jug on the windowpane. Sipping it, he let his mind empty and his eyes wander from point to point in the dormitory. The diamond shards of moonlight shining through the Black Lake. A stack of textbooks next to his bed. A poster of a Quidditch association tacked onto the wall.

He paused, heart pounding. Stepping quietly, he took a closer look at the poster. The Kenmare Kestrels grinned and waved at him from it. Below the team name was the phrase, "Members of the National Quidditch Association of Ireland (N.Q.A.I.)." The acronym had made an interesting thought pop into his head...

Next morning, he grabbed both John and Molly by the sleeves of their robes after breakfast. Pulling them into their usual empty classroom, he announced, "I had a thought. The only thing David Knight could say when he came out of the Forest was 'hound,' right?"

"Right," said John. Both he and Molly looked highly confused, as usual.

"But why the word _'hound?' " _Sherlock said, emphasizing the word. "Bit of an odd choice, isn't it? I mean, it's an older word, not something people say a lot nowadays."__

"If David saw an enchanted dog, why wouldn't he just say 'dog,' is that it?" Molly said excitedly.

"Exactly." Sherlock concealed a grin; Molly was always a hair quicker on the uptake than John. "I mean, Henry uses the word 'hound' too, but just because it was what his brother used. What if, though, the word isn't really a word? What if it's an acronym?"

"H.O.U.N.D.," John spelled it out. "Like an organization."

"Yes. David Knight saw something about that organization, something he wasn't supposed to see."

"But what was it for?" Molly pondered. "Who was in it?"

"We already know the first answer," Sherlock said. "Students interested in magical creatures and spell inventions. Now we just have to figure out who was involved."

"How?" said John.

"Leave it to me."

Sherlock's last class that day, Charms, let out early due to a batch of students' Growth Charms backfiring. So, Sherlock dashed down to Professor Snape's dungeon, where he knew the seventh-year Slytherins were finishing their lessons. Shivering slightly in the drafty corridor, he waited outside the Potions classroom. When the bell rang, a tiny handful of N.E.W.T. students, five or six in all, came out of the dungeon, bringing a strong scent of Polyjuice Potion with them. Spotting his quarry, Sherlock called, "Fletcher!"

Mundungus Fletcher turned at the sound of his name. "Well, 'ello, 'olmes," he said gruffly as the younger boy ran up to him. "Wantin' anythin' today? On'y we'll 'ave to conduct business someplace else, lad."

"No, no, it's not that," said Sherlock hurriedly. He led Fletcher away from the Potions classroom, to a side corridor near the main route to the Slytherin dormitories. Once making sure no one was within earshot, Sherlock said, "That friend of yours you told me about, the one who saw magical experiments last year?"

"Yeah?" said Fletcher, a wary look in his eye.

"Did he say anything about the people he was meeting? Anything at all?"

Fletcher gazed fixedly at a point above Sherlock's head. Knowing he was thinking back, Sherlock allowed him the time to remember. At last, Fletcher said slowly, "Not a lot. 'e didn't wanna be associated with 'em after what 'appened to the ones'at got caught. Expelled, see."

"But he would've trusted you," Sherlock encouraged him.

A grin spread across Fletcher's face. "Tha's right, Will does trust me," he said in a satisfied tone. Glancing back at Sherlock, he added, "The real question is, can I trust you and your mates if I tell you more about Will Harris?"

"We'll be discretion itself," Sherlock said, using a phrase he'd learned from Mycroft.

Fletcher nodded. "Well, 'ere's what Will said," he said. "It was a student group, wantin' t'know more'n they should, like I told you. Five of 'em were the sorta leaders, an' they 'ad a bunch more students with 'em, from all diff'rent 'ouses. 'Bout fifteen in all."

"And did that group have a name?" Sherlock said, his heart pounding.

"I think Will said somethin' about that," said Fletcher. "Can't remember quite right. Somethin' to do with dogs."


	7. Project H.O.U.N.D.

After speaking with Mundungus Fletcher, Sherlock rounded up John and Molly after dinner. Although there was a slight chill in the air, the past couple of days' rain had subsided, so Sherlock suggested they speak out on the grounds. His excuse was that it was a beautiful evening, but he knew that the grounds would offer them some privacy as well. The three of them went down the sloping lawns to walk along the edge of the Black Lake. The smell of the rain-washed leaves tingled in Sherlock's nostrils, a soothing scent.

"So, Sherlock, what did you find out?" Molly asked. As she spoke, she crumbled one of the slices of brown bread she'd brought from dinner. She handed a slice to each of the boys.

"Well, I talked to Fletcher," Sherlock said. "The word 'hound' _was _an acronym. It was a student organization, and his friend Will Harris went to a meeting to see what they did."__

__"Is it still around?" John asked thickly. He was eating the bread Molly had given him, but at a patronizing look from her he desisted._ _

__"No," said Sherlock. He tossed a bit of his bread into the shallows and watched as small fish swished around it busily. "Fletcher said that some of the members got caught doing...whatever they did. They got expelled. But," he continued as Molly opened her mouth to ask a question, "some of them got away. Fletcher only said 'the ones that got expelled.' So there are probably a few more who are still at Hogwarts."_ _

__"And performing experiments that are both illegal_ and_ immoral," Molly growled. As a lover of all nature, both ordinary and magical, Sherlock knew she was angrier about the experiments than both him and John.

"So what do we do next?" John said.

"Well, figure out who's still here at Hogwarts," Sherlock answered. "Then work out which of them is connected to Henry's mutant dog."

"How?" asked John. "They're not likely to admit to it, are they?"

To Sherlock's surprise, Molly spoke for him. "No," she said. She tossed her slice of bread into the air, pointed her wand at it, and said, _"Depulso." _The bread flew away from her and landed with a_ plop_ in the middle of the lake. "What I was going to say was: students aren't likely to admit a connection to Henry's hound. But we can always use some kind of information to...persuade them." 

Sherlock couldn't contain a grin. They watched for a moment as a tentacle rose out of the lake. The giant squid scooped the bread under the water, and they turned back toward the castle. As they neared the doors, John said, "We'll have to find the students' names."

"Easy enough," Sherlock said. "Filch keeps records of all student punishments, including who gets expelled. The ringleaders will be in there. We'll go there now."

Sherlock led the way through the castle to a small, dingy door off a forgotten corridor. The three of them hid behind a statue of a witch holding a baby hippogriff. "See if Filch is in, Molly," Sherlock said quietly.

_"Homenum revelio." _After an uneventful moment, Molly said, "Nope." The trio ran to the door, which John unlocked. The small, dingy office was lit with a single oil lamp and smelled vaguely of fish-and-chips. File cabinets lined all the walls, and the three split up to examine them. John was the first to speak: "Found something." He pulled open a drawer labeled_ Expulsion and Probation Cases_ and they riffled through it quickly.

Sherlock had just spotted a file labeled "Project H.O.U.N.D." when a soft meow came from the door. The three turned and, to their horror, Filch's scrawny dust-colored cat Mrs. Norris was glaring at them with her red eyes. "Let's get out of here," he said, stuffing the file in his robes. They ran past the cat, locking the door behind them, and didn't stop until they reached the dungeons.

The Slytherin common room was virtually empty, thankfully. They chose a table at the edge of the room, and Sherlock opened the stolen file, Molly and John peering over his shoulders. The parchment was still white; obviously this was a recent case. Sherlock spread the documents carefully over the table. There were twelve sheets in all, the one on the top being a description of the case. Tucked in the very back was a small magical photograph of a batch of students. Sherlock bent over the first sheet to decipher Filch's tiny, cramped handwriting.

" 'Name: Project H.O.U.N.D.,' " he read to John and Molly. " 'Crime: Unapproved to illegal magical experimentation by a group of students. Experiments ranging from creation of new incantations to magical manipulation of plants and animals. See individual files for specific experiments and suggested sentences.' "

The list was fairly long. Eleven students had been apprehended, though Sherlock knew there were more. Three students, one of whom had been a seventh-year, had been placed on academic probation for creating relatively harmless charms and jinxes. However, the other eight had all been expelled for their experiments, from putting unalterable Growth Charms on rats to breeding a unicorn and a hippogriff. Five of the students - Leonard Hansen, Jack O'Mara, Mary Uslowski, Rick Nader, and Elaine Dyson - had surnames whose initials spelled the group name.

"Jesus," Molly muttered, reading the unicorn-hippogriff case with a revolted expression.

"Sherlock, look at this." John's tone made Sherlock look up from examining the sheet. His friend was holding the photograph, and John handed it to Sherlock. All three of them looked at it in stunned silence for a minute. Beryl Stapleton was among them, hidden in the very back, but that was not what caught their eyes.

"Oh, my God," Molly breathed.

Standing beside Stapleton, also half-buried but recognizable, was Henry Knight's Ravenclaw friend Bob Frankland.


	8. A Spot of Blackmail

After discovering Project H.O.U.N.D., Sherlock, John, and Molly were nearing the end of Henry Knight's case. The "hound" was perfectly real; it was now just a matter of finding out who was responsible for it, and for destroying the dangerous creature. From Filch's files they knew of only one former project member who was still actively experimenting: Beryl Stapleton. Perhaps, with a little of Molly's "persuading," she would be able to tell them more.

On Halloween morning, all of Hogwarts Castle awoke to the smell of baking pumpkin. Sherlock inhaled the smell happily as he walked through the main corridors, looking forward to the famous all-dessert feast tonight. When he entered the Great Hall, he ducked as a cloud of live bats fluttered down from the pale blue ceiling. Hoping he wouldn't find guano on his plate in a moment, he sought out John at the Gryffindor table. "We need to talk to Stapleton," he muttered to his friend. "She might be responsible for Henry's hound, or know who is."

John glanced around. "And how are we going to make her talk?" he asked. "Threaten to tell Professor Flitwick about her experiments on the cat?"

Sherlock shook his head. "No, we said that when we met her. I think threatening to rake up the past will scare her more." John shook his head resignedly, but agreed to the plan. Molly agreed to have Soo Lin Yao find Stapleton and tell her to meet the second-years after lunch.

Soo Lin was as good as her word. After lunch, Molly, Sherlock, and John went into the Entrance Hall to find Stapleton waiting for them at the foot of the marble staircase. Sherlock led the other three into their preferred first-floor classroom. Once the door was locked, Sherlock pulled out the old photograph they'd found in Filch's office.

When Sherlock held it up, Stapleton's face whitened. She opened and closed her mouth several times, but no sound came out. Finally she said in a croaky voice, "Where did you get that?"

"In the folder on Project H.O.U.N.D.," Sherlock answered coldly. "As you can see, you're in the shot. You're still here at Hogwarts, which means Filch probably didn't look too closely at this. But I think everyone from Filch to Professor Dumbledore would be interested to see you in it, if they looked a little closer."

"Are you _blackmailing _me?" Stapleton sputtered.__

"We seem to be," John muttered. Sherlock threw him a glare and continued.

"Who else in this photograph is still at Hogwarts and still experimenting?" he demanded.

Stapleton obviously saw no way out of her situation. She gave a long sigh and said, "Fine. Sit down."

The four students sat at a nearby table. "Not everyone was there the night we got caught. I wasn't, but I heard about it after," Stapleton said. Sherlock kept a hold on the picture, but allowed her to point at various figures. "Stephan Paisley is still here, but he's in Hufflepuff, so I don't talk to him anymore. Bob Frankland and Anne Uslowski are still here too. Anne was lucky she was only put on probation; her sister Mary was one of the leaders, and she got expelled."

"And Frankland?" Molly asked, unable to keep a note of excitement out of her voice. "Does he still experiment?"

"Unless you made Henry Knight's hound and want to admit it," said Sherlock.

"I know better than to experiment on an animal more dangerous than a housecat," snapped Stapleton.

"But does Frankland?" Sherlock pressed her.

"I can see I'll never get out of this if I want to save my own neck," she said. She closed her eyes, as if making a difficult decision. After a moment, she opened them and said, "Yes. Bob still does experiments on his own too. He was close to Leonard Hansen, a seventh-year, head of the project. They were working on designing animals for battle, to offer to the Ministry of Magic once Leo was out of school. Their work involved dogs, but the group got caught before they finished."

Sherlock, John, and Molly all exchanged glances. The thrill of discovery was coursing through Sherlock's veins, but the other two looked worried. He supposed they were thinking about how Henry would react to this news. He probably wouldn't be too thrilled to hear David's best friend was responsible for his hospitalization. Well, they couldn't control reactions. "Do you know if Frankland is working on anything tonight?" Sherlock ventured a guess.

Stapleton frowned. "He will be," she said coldly. "He told me he was almost done working out 'the kinks.' I suppose telling you won't hurt, now I've already destroyed my friend."

Sherlock decided it would be best not to acknowledge that point. "You can go," he said.

"I want the photograph. Make sure you don't turn on me even when I've helped you."

_This girl knows her stuff, _Sherlock thought grimly. He handed the picture to Stapleton and she left the room, giving the image one last look before tucking it into her robes. As the door closed, he turned to the other two. Molly's brown eyes were the size of Sickles. "So what do we do?" she asked Sherlock.__

"We get Henry and follow Frankland into the Forest. Tonight," he answered.


	9. The Shrieking Shack

Sherlock, Molly, and John all spent the rest of the day in a nervous state. Soo Lin Yao pointed Bob Frankland out to the other three; he was a tall, lanky sixth-year with flyaway mousy brown hair. They would definitely be able to recognize him later, when he snuck out to the Forbidden Forest (or wherever he kept his beast). John had also instructed Henry to come along, to see the laying of his ghost. Still, the Hogwarts Halloween feast couldn't disappoint, not even three preoccupied second-years. The House tables groaned under dishes of candy and sweets: Chocolate Cauldrons and Exploding Bonbons, shimmering blocks of ice cream and sorbet, and everything from Pumpkin Pasties to freshly baked pumpkin pies.

As they'd agreed, the three friends and Henry Knight got food from their own House tables and carried them out into the grounds, which were still light out at six o'clock. They all sat down underneath a weeping willow on the edge of the Black Lake. Molly, to the boys' surprise, also brought a small stack of books. "What're those for?" John asked through a mouthful of treacle tart.

"Well, we're tackling a monster dog tonight, aren't we?" she said. She absentmindedly nibbled a chocolate-chip cookie and thumbed through _The Standard Book of Spells, Grade 4. _"I got the higher grades from the library," she explained. "In case we need a few extra spells. This is a magically influenced animal, remember."__

__"Good thinking," said Sherlock. Molly reddened a little, but smiled at the compliment. He went on, addressing the group. "We should all go over what spells we know that might help."_ _

__As they brainstormed, John took notes in the little notebook he carried in his pocket for the school newsletter. When they were done, he said, "Well, we've got a decent bunch of spells here. We can all Disarm and do Freezing Charms, and Molly can do the Banishing Charm. We've also got a few good jinx-type spells: Furnunculus, Expulso, and the Leg-Locker and Full-Body Bind Curses. Henry, what's this one, 'Protego'?"_ _

__"Shield Charm," said Henry. His voice was calm, but his eyes darted to the Forest constantly. "Makes an invisible barrier between the caster and the attacker."_ _

__Sherlock tossed one of his cookies into the air._ "Protego!"_ he said. Though he couldn't see the barrier, the cookie stopped in midair above his head. John and Molly copied him, practicing the charm until they got it (John took a few tries; Charms wasn't his best subject). "That should be really helpful," Sherlock said once they were finished practicing. "Thanks, Henry." 

____"Don't mention it." Nobody spoke much after that point. All of them were busy thinking about what they'd have to do. They went their separate ways after returning their plates to the Great Hall. Soo Lin would send word to the others once Frankland left Ravenclaw Tower. Sherlock spent his evening near the fire in the Slytherin common room, casting the various charms and hexes on a fly buzzing in the window._ _ _ _

Just after nine o'clock, Sherlock heard a funny scratching at the common room door. He opened the stone door and stood aside as a tawny owl flew silently in: Soo Lin's owl. From the loose strings around its leg, it had already delivered the signal to John and Molly. Sherlock tore off the third note and read it: _He's in the common room. Go now. _He folded the note, put it inside his robes, and set off.__

Sherlock made his way through the silent castle without incident. He'd been out of bed after hours before, and was grateful he'd only encountered Peeves, the school poltergeist, once. He hid behind the statue of a winged boar outside the Great Hall, the agreed-upon meeting place. After a few minutes of waiting, Molly emerged from behind the Hufflepuff tapestry, a garden scene bordered with gold and black thread. Soon after, John and Henry came down the marble staircase leading to Gryffindor Tower, wands out and glancing nervously into the shadows. Without lighting their wands, the four students waited.

They didn't have long to wait: a long, lanky figure appeared at the top of the other marble staircase. Henry let out a gasp, which Sherlock silenced by clapping a hand over the other boy's mouth. The four waited until their quarry eased through the front doors before following him quietly. They followed Bob Frankland across the moonlit lawns towards the Forbidden Forest. Beside Sherlock, Henry was shaking with rage. When they paused behind the greenhouses to avoid being seen, Sherlock laid a hand on Henry's shoulder and shook his head. There would be a time for confrontation, but it had to wait until they had Frankland cornered. Slowly, they inched back out into the open.

Suddenly Frankland veered off, away from the Forest. He was heading for an ancient, gnarled tree standing near the edge of the Black Lake. At his approach, the tree's clublike branches slammed down to the ground, forcing the boy to leap backwards. As the Whomping Willow lashed out with thinner, whiplike limbs, trying to reach him, Frankland pulled out his wand. Sherlock pulled the others behind a bush to watch. _"Wingardium Leviosa!" _Frankland said. A small branch spun into the air and, directed by Frankland, poked the Willow in a knot near the base of the trunk. To the younger students' amazement, the tree froze, and Frankland slipped down through a gap in its roots.__

"Come on," Sherlock breathed, and he led the way toward the frozen Willow. He shepherded the others in and followed them; he slid down a narrow, earthy slide and hit the ground again with a soft thump. He'd landed in a low, dim tunnel, more like a huge rabbit warren than anything, with the Willow's roots protruding from the ceiling and walls. The other three were all standing nearby, their robes smudged with dirt from the fall. Sherlock lit his wand and led the way through the tunnel. There was no sound except for their footsteps and Molly's quick, nervous breathing.

At last, they came to the foot of a worn, stone staircase. With no other option, they went up it until they found an open trapdoor. Hoisting his head and shoulders through it, Sherlock found himself in a dim room with dust-covered wood floors. A set of footprints broke the dust, going up a narrow staircase. Somewhere above his head, he could hear the house creaking and the wind whistling through gaps in the walls. As the others climbed through the trapdoor, John whispered, "We're in the Shrieking Shack, aren't we?"

Sherlock nodded, and motioned for the others to follow him. Quietly, they climbed the groaning wooden stairs. He tried very hard not to think about the chunks torn out of furniture all around them, or the banisters hanging off the edges of the stairway. Something more than ghosts had done that damage, he knew.

A door stood ajar at the end of the second-floor hall. From it, Sherlock could hear a weird, low rumble. Flashes of green and blue light, byproducts of spells, danced in the open door gap. Wands at the ready, he, Henry, John, and Molly approached the door. After a moment's hesitation, Sherlock kicked it open.

"Evening, Bob Frankland."


	10. The Hound of Hogwarts

Bob Frankland, upon hearing Sherlock's greeting, jumped and spun around to face them. His wandlight revealed nothing but fury in the long, thin face. Sherlock and the others advanced into the room. It was a large dining room, judging from the long table and chairs shoved against the walls. Like the furniture in the rest of the Shrieking Shack, the chairs and table in here had been torn and shredded, parts of them chewed away completely. Behind Frankland, a box large enough to contain a draft horse sat pushed against the wall. Animal bones were littered around the front of it, some with pieces of pinkish flesh still hanging from them. The whole room stank of rotting, decaying meat.

"What are you doing here?" Frankland snapped. "No one knows how to get in here but me."

"You should buy an Invisibility Cloak, Frankland," Sherlock said calmly, his eyes never leaving the other boy's. "You were very easy to see and track."

"Why?" said Henry's voice at Sherlock's left. It was shaking and cracking with emotion. "You were David's best friend. His friend! And you set that...that _thing _on him, didn't you?"__

__"Henry," said John in a calming tone. He laid a hand on Henry's shoulder, but the other boy shook it off. He was trembling with rage now, and his voice reached a hysterical pitch._ "Didn't you?"_

"No!" shouted Frankland, looking alarmed. "Henry, you don't understand, I took David to the Project H.O.U.N.D. meeting and my dog got loose! It was an accident!"

"Rubbish!" snarled Henry. "If it was an accident, why did you erase his memory? He'll never get out of St. Mungo's now, and it's all your fault!" Underneath the boy's tone, Sherlock clearly heard another snarl. The thing in the large box was rattling its edges, scratching at them.

Frankland saw Sherlock looking. "It's magically reinforced. It shouldn't be able to get out."

"Shouldn't," John repeated sarcastically. Sherlock ignored him; he only had eyes for Frankland.

"Answer Henry, Frankland," Sherlock commanded.

Frankland gave a deep sigh. "Once David had seen, he told me he wouldn't let me go on with it. But think, Henry!" Frankland said, seeing Henry's face twist in rage. "Think how useful it would've been to wizards: animals for battle that could never be beaten! We _had _to go on with the experiments!"__

__"And my brother had to be shut up. Is that what you're saying?" spat Henry._ _

__To his credit, Frankland looked deeply saddened. But there was still a maniacal gleam in the cold blue eyes. "One wizard was sacrificed for the good of many," he said shortly._ _

__Henry made an angry movement forward, but Sherlock restrained him with his free hand. "It's over, Frankland," Sherlock said clearly. "Whether you thought it was right or not, you took David Knight's life away when you took his memories."_ _

__"You'd better come with us now," said Molly, her wand hand steady as it pointed at Frankland._ _

__"But first, you need to destroy that dog," Sherlock said, pointing at the box. It was rattling more than ever, and he thought he heard the hinges groan._ _

__To everyone's surprise, Frankland grinned. "I wiped my best friend's memories to protect my work," he said evenly. "You think I'm going to let this stop me?"_ _

__It all happened very quickly. Frankland whirled around, pointing his wand at the wooden crate's hinges._ "Bombarda!"_ he roared, diving aside as the hinges burst from the door. Wood splintered everywhere, a piece hitting Sherlock painfully above his left eye as it flew. And there it was, coal-black and snarling, red eyes glowing, the size of a horse: the Hound of Hogwarts. 

____With a keening howl, the hound leapt from its crate into the dining room. Its cries mingled with screams as Molly, Sherlock, Henry, and John scattered. Sherlock dodged the beast as it charged him, colliding painfully with a dining-room chair. From underneath it, he saw the creature lunging at Henry, and he cast a Shield Charm between them. Instantly the invisible barrier shot up between the monster and Henry, and Sherlock scrambled out from under the chair.____

"Sherlock!" shouted John. The hound had spun around, knocking aside more chairs as it ran for Sherlock. Panicking, he fired every curse and hex he could think of at it, but the animal merely kept charging him. Its skin and fur must've been modified to be extra-strong, like dragon skin. Sherlock knew a moment of pure terror as the black hellhound bowled him over, and he felt its hot, stinking breath at his neck - 

_"Incendio!"_

________The shriek rang through the room and Sherlock glimpsed blinding orange light above his head. It barely missed the hound, blasting a hole in the wood wall just above its head and lighting it on fire. But the Fire Curse did singe its fur, making it howl in pain. Sherlock took advantage of its distraction and gave a huge heave, and the monster rolled off of him. He could see Molly on the other side of the room, her wand pointing at the wall._ _ _ _ _ _ _ _

________A figure dashed past her, blue-fringed Ravenclaw robes swishing. Frankland had run for it, leaving the four younger students alone with the hound. But not for long: still howling from its burn, the animal lunged after the moving target. John pulled Henry out of the way, and all four sent hexes after it to chase it out._ _ _ _ _ _ _ _

Shakily, Sherlock got to his feet. _"Aguamenti," _he stammered, and a jet of water poured onto the fire, extinguishing the flames. He could still smell the stench of the hound on his robes. Henry and John stood huddled in the corner; both boys' hands and faces were covered with cuts from the exploding crate, but Sherlock could see no bites on them. He crossed over to Molly, who was still frozen. Her face was starkly white as she continued to stare at the hole in the wall. He put one arm around her, and felt her shuddering.__

_________Sherlock opened his mouth to thank her for saving him, but something else stopped him. A high, piteous, human scream echoed up through the halls. They thundered down through the Shack, following the screams. They heard a nauseating ripping sound, the sound of robes and flesh being torn. All the while, the screams rang in their ears. At the foot of the stairs, the horrible sight met their eyes._ _ _ _ _ _ _ _ _

_________The hound was crouched over Frankland. Sherlock couldn't see him, but torn shreds of Hogwarts robes lay all around the monster's paws. He could see blood dripping from the gigantic fangs, and registered with horror that the screaming had stopped. There was a moan behind him and a low thump, and he turned. Henry had fainted onto the stairs. John and Molly, though still standing, looked as if they might be sick._ _ _ _ _ _ _ _ _

_________"End it, Sherlock," John said softly over the crunching of bones. "Please."_ _ _ _ _ _ _ _ _

_________Sherlock turned back to the monstrous experiment, sated now with its own creator's flesh. He gave a deep sigh. "We'll need to do it together. One spell won't be enough."_ _ _ _ _ _ _ _ _

The three friends raised their wands. Sherlock saw his own hand shaking with awareness of what he was about to do. In unison they spoke the words: _"Avada Kedavra."_

Three jets of green light struck the monstrous figure. The hound quivered for a moment, its hulking outline illuminated with green, and then it fell with a whimper to the dusty, bloodstained floor.


	11. Case Closed

For a few days, the Hogwarts teachers didn't find out exactly what happened in the Shrieking Shack that Halloween. That night, because they'd used the Killing Curse on the hound, Sherlock and Molly decided it was best to bury it, which they did, in the shadow of the Whomping Willow. The remains of Bob Frankland were found the next evening, and all anyone could guess was that he'd had a mishap with a magical creature, perhaps an angry hippogriff or a badly-trained thestral. Upon the pricking of conscience, Sherlock, Henry, John, and Molly all went to Professor Dumbledore and told him the story (minus the curse; they told him Frankland had killed it trying to defend himself).

The first week of November brought a hard frost to the grounds and Forbidden Forest. Though it was chilly outside, Sherlock left the Great Hall at lunchtime with John and Molly. He'd been thinking a lot about the case, and wanted to discuss it with them. They walked along the banks of the Black Lake in silence at first.

Finally Sherlock spoke. "Well, how are you two doing?" he asked awkwardly.

"Fine," they both answered, a little too quickly for Sherlock's liking. At a look from him, Molly sighed and elaborated. "We killed it," she said flatly. "We used the Killing Curse on the hound. All three of us should be in Azkaban for that."

"Did we really have any choice?" John asked quietly. The other two didn't answer. Sherlock, though generally not disposed to philosophy, had been wrestling with that question for days now.

"What about Frankland's parents?" Molly asked Sherlock after another silence. "Have they asked anything about how he died?"

"No. The school's told them it was an accident in Care of Magical Creatures."

"Well...sort of true, I guess," said John. They continued walking, past the weeping willow they'd sat under just a few days previously. Then another question burst from John, as if he couldn't help himself. "Why did Frankland have to die like that? I wouldn't wish it on anyone."

The other two thought for a moment. It was Molly who answered first, to the boys' slight surprise. "Well, he was making the hound to sell to the Ministry for battle," she said softly. "He was designing it to hurt and kill other people, and he didn't seem to care how many people he had to hurt to keep it quiet. Then it turned on him."

"And so wickedness falls into the trap it's made for another," Sherlock said. Seeing the others' confused faces, he said, "It's something my brother Mycroft says sometimes, when a plan designed to hurt others turns on its maker. He sees it a lot in politics. What you create comes back to you, it becomes your fate."

"That still doesn't mean he deserved it," said John stubbornly.

"No, it doesn't. It just happens whether you 'deserve it' or not." They walked on. Out in the center of the lake, Sherlock could see the giant squid waving a tentacle above the water. Then he asked John, "Has Professor Binns asked you for another serial yet?"

John shook his head. "The newsletter doesn't start running until later this month," he said. "But I do want to write this case up. Is it all right if I use our names? Thanks to Donovan, everyone knows it's us now."

"We might as well," said Molly, shrugging. "What are you going to call it?"

"I thought I'd call it 'The Hound of Hogwarts.' "

__Sherlock felt a grin tug at his mouth. "You have a knack for names, John Watson," he said. "I should let you title my essays for me."_ _

__The other two laughed for a moment, the first time he'd heard them laugh since Halloween. They lapsed into silence quickly. Sherlock knew it would be a long time before their actions that night, and the resulting questions, stopped haunting them. But that day would come eventually. The three friends stood in silence at the lake's edge for a while before returning to the castle across the frozen grounds._ _

__The End_ _


End file.
